package code20210906;

public class C509 {

	public static void main(String[] args) {
		System.out.println(fib(4));

	}
	public static int fib(int n) {
		if(n==0) return 0;
		if(n==1) return 1;
		return fib(n-1)+fib(n-2);
    }

}
